coffey



Oct. 23, 1-928 I o. L. COFFYEY DROP PI T MECHANISM FOR UNWHEELING LOCOMOTIVES 4 Sheets-Sheet 1 Original Find Jan. 10. 1925 -Qct. 23,1928. O-L-COFFEY 'Re.1 7,l16

DROP PIT MECHANISM FOR UNWHEELING LOCOMOTIVES 4 Sheets-Sheet 2 Original Filed Jan. 10. 1925 0a. 23,}1928. Re. 17,116

DR P PIT- MECHANISM FOR UNWHEELI NG LOCOMOTIVES 4 Sheets- Sheet 4 ofvarious motives. tion is to provide der, and particularly in such a operative to selectively transport wheels from separate locomotives on v a Reissued oct. 23; 192a.

'- UNITED STATES f Re; 17,116

PATENT OFFICE."

.osen. L. corner, or

Drier-rm MEGHANISM roe unwImnLINc LOCOMOTIVES.

Original at. 1,564,828, dated December 8, I925, Serial no. 1,518, filed January 10, 1925. Application for r This invention-relates to so-called drop pits for removing heavy wheels from vehicles kinds,specifically: railroad loco- The principal object of the invena it construction and wheel carrying mechanism operating therein adapted to transport a pair'of wheels from a vehicle, such as a locomotive, to'a point on another track in such a position and condition that theyrnay be rolled away for work to be done upon them.

The invention consistsin mechanism capable of attaining the foregoing and other objects; which can be comparativelyeasily and cheaply made; which is satisfactory in use and is not readily liable to get out of ormultiplicity of separated-tracks 'to a common point of d livery of the wheels for worlrthereon.

More; particularly the A invention consists in numerous features and details of construction' which will be hereafter more fully described inthe specification and claims. Referring to the drawings in which like numerals designate like parts throughout the several Views:

Figure 1 is a plan view of mechanism illus-.

tratingthis inyention in its preferred form. Figure 2 is a side elevation taken on the irregular line 2-2of Figure Figure 3 is an end'levation irregular line 3 -3 of Figure 1.; j V

Figure 4 is a reduced size, changed position view of the parts of Figure 3 taken from the extreme right hand end of Figure 1. Figure 5 is a plan view of he complete pit, equipped with the mechanism of this invention, showing the-same applied in curved form as would be required if applied in or in taken on the proximity to a round house.

. Figure 6 1s a side elevation, taken on line 6-6. of Figure 5.

The mechanism of this invention is applir of an intersecting pit 16, preferably but not necessarily entirely open at its top, there being in the bottom of the pit a track 18 along device which is of the box girders 62.

' tr ated, longitudinall .tendingparallel wit 1 rails 18 and forming a reissue flled'september 10, 1928. Serial No.305-,085.

trated, made up of side frames 22 and cross beams 24, rigidly connected thereto, the side frames including blocks 26 located over the load on therails 18 and adapted when the trolley exceeds a certain point to, through. the

spring construction 28, interposed between I the trolley and its supportingl wheels 30, rest upon the track rails 18 an thustake the strain oil the wheels all as more fully described and claimed in the companion apphcation (Serial No. 1,517) for Patent No.

, 1,586,783 dated J une 1, 1926. The trolley as a whole is propellable along the rails 19 by any suitable means, in the particular case here illustrated by -the rocking of hand manipulatable levers'32, equipped with ratchet dogs 34 selectively engageable with the teeth 36 on ratchet wheel 38, on the shaft 40 of the adj acent wheels 30, all as more fully described and shown in said companion application.

Rising from and rigidly attached to four corners of the trolley 20 are four load carrymg screws a worm wheel 44 meshing with a suitable worm 46 enclosed in an oil or grease retaining case 48. The worms 46 are connected together in pairs by shafts 49, each carrying a evel pinion 50 meshing with another bevel pinion 52. These twdlast mentioned pinions are on a common shaft 54 carrying a gear 56 driven by a pinion 58 on the shaft of an electric motor 60 or other suitable source of power, receiving its energy from a source not shown, outside the machine. Each two cases 48 over a given track rail 18 are rigidly connected to box girders 62 made up, as clearly shown in Figures 3 and 4, of spaced channel irons. Each two cases 48, which are opposite each othertransversely of the track are connected together by cross-beams 64 rigidly secured in position by any suitable means, as, for instance, the angles 66, suitably securedto these cross beams and The box girders 62 are carried by bolts equipped with Spreaders 68,

cable to a multiplicity of adjacent but spaced which insure the, side channel irons of the railroad tracks 10 -12 and 14 crossing the top girders being almost the same distance apart and consequently capable of separably interlitting, as shown in Figure 3, with depending mcmbcrs-in the particular case here illusdisposed girders 72, ex-

part of wheel sustainingtable 74. equipped 42, each having threaded thereon the adjacent channels 6 disposed of.

. 20 with the upper 25 6264 can be lowered with rail sections 76, selectively interfittable with at least one of the'tracks as or 14 which carry the locomotives and the track, as 12, on which theremoved wheels arefinally Thetable is composed of a pair of girders under each rail-section 76 and additional girders outside of the girders under the rail sections, to support. side platforms.

15 slots 86 in the side walls of the pit 16, and rest upon stationary supports 88 to a retracted position inwhich they are drawn inward sufficiently to clear these supports and thus permit the wheel table'to rest upon and travel frame appears hereafter. From the foregoing, it clearly appears that be locked in position 14 and that when so in the tracks 10.-'12 or positioned, the frame and the trolley can then be run along track 18 (asshown in Figure 4) 'without' in any way interferin with such locked in position wheel table 74. Upwardly projecting guides 90 having aces 92 and 94 angularly inclined in planes at approximately right angles to each other insure the accurate interfitting of the lifting mechanism and the wheel-carrying table 74 when the operator causes the lifting mechanism to move from the position of Figure 4 upward to the position of Figure 3.

Attention is called to the fact (clearly shown in Figure 4) that the tops of the screws 42 amply clear the projecting mem- 40 bers, specifically the girders 72 on the lower' ""side of wheel tables that as many tracks 74, the significance being l0-14 asdesired, intersected by the pit 16, said tracks except one being equipped with a wheel table 74 and that the trolley 20 may then go to any track having a table 74, connect up withthat table as shown in Fig.

3' have the latches 78 released, and then lower the table 74 to a oint below the tops of the screws 42 and thereupon carry said table under the tables of any other intervening tracks to the opening in the track which did not initially have a'.wheel table, and by raising the carrying wheel table, place it in that track. This is of importance in that the mechanism is capable of serving a multiplicity of tracks to deliver wheels from locomotives on those tracks to a common track, 12, for work upon those wheels, this while leaving all of the tracks, except the service track 12,. complete so that locomotives-or other machines to be dewheeled can move at will over the different tracks, regardless of the position of the trolley 20 along the-rails 18 in pit 16. This lowering of the table 74 The wheel table 74 is equipped with recip- 62*64 as more fully] the wheel. table 74 can I mechanism and the wheels .clear the wheel table in any other track '1 -14 under which the wheel is to be carried.

may be provided, all ofto the position in Figure 4 is rendered possible, as clearly shown in Figure 1, by omittingall obstructions in alignment with the screws 42 from the table structure 74.

In the operation of the entire mechanism, assume that the parts are in initial position of all the figures, except Figure 4, and that a locomotive 96 is standing with its wheel 98 on. rail sections 76 of the table 74, installedfor the time being, ifnot regularly belonging in track 10. The operator now starts motor to ultimately rotate worm wheels 44 in unison to slightly raise lifting frame 62-64 and consequently wheel table 74 and wheels 98 to a pomt' at which latches 78 can be freely B0 the companion application, heretofore mentioned. WVhen this extreme upward position is reached, the motor 60 is stopped and the operator blocks springs, notshown, on the locomotives and detaches the wheels 98 which now rest only upon rail section 76 of table 74. The operator now starts the motor 60 in the o posite direction, thus causing the entire mechanism shown at the top of Figure I and between the guides 100 on opposite pit walls to descend to such point along screws 42, say the position of Figure 4 or lower, wherein the lifting 98 thereon entirely The moment the wheels 98 descend to a point where. they only are carried by the table 74, the normal position of Figure 2 in which they slightly clear the rails 18. When the wheels have been lowered sufficiently, the operators manipulate one or both of the levers 32'to propel the trolley 20 and everything on it along the pit until the table 74, which has up or otherwise secures the 10.1 springs '28return the blocks 22 to the i just been removed from track 10 is in proper position with reference to the service track,

say track 12, .on which the wheels are to be stopped taken away. The operator having motor 60 before manipulating starts the motor of the table 74.

levers 32 now to cause upward movement placed. In this condition of This movement is continued until the latches 78 may now be returned to original position in track] 10 b reversing the operations described or t is table'inay be 1e t indefinitely in track 12 and the machine inanipulated in obviousvnianner'until the parts assume the position of Figure 4 whereupon thetrolley 20 can be moved along the track 18 to another track, as 14, -whose table 74:, with or without wheels thereon, is to be transported into any track 1014 whichhas no table 7 in it, under the conditions just described, track 10,

The drawings show a completely open pit 16 but there is nothing in the structure-of the invention which requires any surface opening between the tables 74 in elevated position or the respective adjacent tracks. 'In" other words, if the pit is made deep enough and the screws 42 are made of corresponding length, the table 74: and wheels thereon may be carried down to a sufficient depth in the pit 16 to carry the wheels under any desired roof construction placed over the top of the pit. In this'aspect, the invention is usable in transporting a track table between two adjoining pit top openings in the sametraclr as Well asunder the conditions shown, wherein the effective openings are in parallel tracks.

In thespecific embodiment of the invention, the plt 16 is curved from the centeref intersection below Figure 50f tracks 1O-l i. ()bviously, if the tracks were parallel to each other, the pit 16 would be straight and at rightangles thereto.

The construction illustrated exemplifies mechanism of the class described in which; the power mechanism for manipulating the lifting carriage includes an electric motor,

and gearing operated thereby mounted on and to travel with the table-engaging carriage or frame; power-mechanism which includes pairs'of worms mounted on the table-engaging carriage and driven bya pair of parallel motor-driven. shafts; the tables are built-up of girders to form a rigid structure; the'tablesand lifting carriage are formed of girders adapted to interfit .or .lap one another; the tables comprise a pair of-longitudinal girders under each rail-section and cross-girders underlyingthem; the" lifting carriage has girders which pass or straddle the cross-girders of a table to directly engage its longitudinal girders; the tables are extended laterally of the rail-sections with girders at the sides thereof; the gears on the screws are confined in lubricant containing cases; the screws pass between pairs of girders on the lifting carmag c and lubricant retaining cases fixed to and underlying sald pairs of girders, so the carriage will be supported by the cases; the

. electric motor is mounted between the girders of the lifting-carriage; the table-latching bolts underlie thcrail-sections on the table, are within the hor zontal :plane of the. girders of the table, and are mounted within pairs of trolley may be manually propelled independently of the electric motor on the lifting carriage; the lifting carriage of girder construction isprovided with a set of guides to rela- .tively position and retain a table on the lifting carriage; so that the-mechanism is specially adapted for heavy-duty service in con nection with. locomotives, and so tha-t the table andcarriage can be operated vertically between the table-releasing and the wheel-transferring positions in a pit of the minimum height necessary for transferring locomotivewheels under other tables.

I claim: I 1. In mechanism of the class described, the

combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means detachably latching it across the pit, and a track in the bottom of the pit passing under said tables, of a trolley travelable along said track, a table elevating ca 'riage,engageable with and separable frein a table, on and reciprocal vertically above the trolley, and movable between .a position where it engages and lifts a table high enough so its latching mechanism maybe released and a position low enough so that the trolley with said table and. the

wheeled load therein may move along said track under one other such wheel table, and

mechanism for raising and lowering said carriage comprising a motor fixedly mounted on and movable vertically with the table-engag-- in g carriage. v

2. In mechanism of the class described, the combination with means passing a wheeled Vehicle over the ground, a pit below it having wheel tables each equipped with means de tachably latching it across the pit, and a track in the bottom of the pit passing under said tables, of a trolley travelable along said track, a table elevating carriage engagcalfne with and separable from a table, on and reciproeal vertically above the trolley,- and movable between a position where it engages and lifts a table high enough so its latching mechanism may be released and a position low enough so that the trolley with said tableand the wheeled load thereon may move long said track under one other such wheel table.

mechanism foriraising and lowering saidcarri-age comprising a motor and gearingdriven' by the. motor, said gearing and motor being mounted on and vertically n'iovable with the table-engaging carriage.

3. In mechanism of the class described, the combination with passing a wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means de- "tachably latching it across the pit, and a track in the bottom of the pit passing under said tables, of a trolley travelable along said track,

a table elevating carriage engageable with and separable from a table, on arid recipro cal vertically'nbove the trolley and movable between a posltion where it engages and-lifts a table high enough so its latching mecha nism may be released and a position low enough so that the trolley with said table and 2 4. In mechanism'of the classdescribed, the

combination with means passing a wheeledvehicle over the ground, a pit below it having wheel-tables each equipped with means detachably latching it across the pit, and a 2 track in the bottom ofthe pit passing under said tables, of a trolley travelable along said track, a table elevating carriageengageable with and separablefrom a table, on and reciprocal vertically above the trolley and mov- .able between a position where it engages and lifts a table high enough so its latchingmechanism may be released and a position low enough so that the trolley with said table Lindthe wheeled load thereon may move along said track under one other such wheel table, and mechanism for raising and lowering said carriage comprising non-rotatable screws having their lowerfends mounted on the trolley, gearing comprising elements threaded 40 to the screws, and an electric motor for driving'said gearing, said gearing. elements and motor being mounted on and movable vertically with the table-engaging carriage.

- 5. In mechanism of the class described, the

combination with means passing a wheeled vehicle over the ground, a pit below it hav- 1ngwheel tables each equipped with means detachably latching-it across the pit, and a track in the bottom of the pit passing under I said tables, of atrolley travelable along said track, a table elevating carriage engageable with and separable from a table; on and re- 'ciprocal vertically above the trolley, movable between a position where it engages and lifts a table high enough so its latching mechanism. maybe released and a position low enough so that the trolley with said table and the wheeled load thereon may move along said track under one other such ,wlieeltable. and mechanism for raising and lowering said carriage comprising screws fixedly held in the trolley and extended vertically for the entire travel of the carnage, worm-wheels threaded to the screws and mounted on and vertically movable with said carriage and gearing fordriving said wheels, mounted on said carriage.

6. In mechanism of the class described, the combination with means passing 'a wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means detachably latching it across the pit, and track in the bottom of the pit passing under said tables, of a trolley travelable along said track, a table elevating carriage 'engageable with and separable from a table, on and reciprocal vertically above the trolley, movable between a position where it engages and lifts a table high enough so its latching mechanism may be released and a position low enough so that the trolley with said table and the wheeled load thereon may move along said track under one other such wheel table. and mechanism for raising and lowering said carriagecomprising non-rotatable screws 'rising from the trolley, extended vertically for the entire travel of the carriage, rotatable ele ments engaging the screws and mounted on saidcarriage, gearingfor, driving said elements, mounted on said carriage, and an' electricmotor mounted on the carriage, for driving said elements.

7. In mechanism of the class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means detachably latching it across the pit, and a track in the bottom of the pit passing under said tables, of a trolley travelablealong said track, a'table elevating carriage engageable with and separable from a table, on and reciprocal vertically above the trolley, movable between a position where it engages and lifts a table high enough'so its latching mechanism may be released and a position low 10 enough so that the trolley withsaid table and the wheeled load thereon may move alongsaid track under one other such wheel table, and mechanism for raising and lowering said carriage comprising four screws non- 0 rotatably held in the trolley, gears rotatable around and threaded to the screws. and a pair i of parallel shafts mounted on the carriage, each connected to drive a pair of said gears, and a motor connecte'd'to drive both shafts, mounted on the carriage. s

v 8. In mechani's'rnof the class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means detachably latching it across the pit, and a track in the bottom of the pit passing under vsaid tables, of a-trolley travelable along said track,

a table elevating carriage engageable with and separable from a table, on and reciprocal vertically above the trolley, movable between a positionwhere it engages and lifts a table high enough so its latching mechanlsm may be released and a posltion'low enough so that the trolley with said table and the wheeled load thereon may move along said track under one other such wheel table, and mechanism for raising and lowering said carriage comprisingan electric motor on the carriage, four non-rotatable screws rising from the trolley,

- worm-gears threaded to and rotatable around the screws, and a pair of parallel shafts on the v "v carriage and driven by the motor, each shaft having a pairof worms engaging a pair of said gears, respectlvely, I

9. In mechanism of the class described, the

' combination with means passing-awheeled Vehicle over the ground, a pit belolw it having wheel tables, each equippedwith means detachably latching it across the pit, one oi said tables having rail-sections thereon and comprising longitudinal and-cross-girders secured together to form a rigid structure, "and; a track in the bottom of said pit'pass ng under said tables, of a trolley. travelaible along said .track, a table elevating carriage vertically reciprocable above the trolley,.movable between a position where it engages and lifts a table which it may be under high enough so 'its latching mechanism'may be released, and a position low enough so that the trolley with said table and a wheeled 1oad-thereon may move alon such wheeled ta 1e, and mechanism-for raising and lowering said carriage, said carriage comprising girders adapted to interfit. with girders on a table.

10. In mechanism of the class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables, each equipped with means detachably latching it across the pit,

one of said tables having rail-sections thereon and comprising longitudinal and cross girders secured together toform a rigid structure, and a track in the bottom of said pit passing under said tables,of a trollentravelable'along said'track, a table elevating carriage vertically reciprocable above the trolley, movable between-a position where it engages and lifts a table which it-may be under high enough so its latching mechanism may be released,

and-a position low enough so that the trolley withsaid table and a wheeled load thereon maymove along said track under one other such wheeled table, and mechanism for raising and lowering said carriage, said carriage comprising pairs of girders adapted to interfit with girders on a table.

11. In mechanism of the class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables, each equipped with means detacha'bly latching it across the pit, one of said tables having rail-sections thereon and.

comprising longitudinal and pairs ofcross V girders secured together to form a rigid structure, and a track in the bottom of said pit passing under said tables, of a trolley travelable 3; ong said track, a table elevating carsaid trackunder one other;

riage vertically reciprocal above the trolley,

movable between a position where it engages and lifts a'table which it may be under high enough so its latching mechanism may be released, and a position "low enough so that the trolley with said table and a wheeled load the'rebn may move along) saidqtrack under I one other such wheeled ta e, and mechanism for raising and lower-in said carriage, said carriage comprising gir ers adapted to interfit with girders-on a table.

12x111. mechanism of the class described, the combination with means passing a wheeled vehicle over'the ground, a pit below it having wheel tables, each. equipped with means de- ,tachably'latching it across the pit,-one of said tables having rail-sections thereon and ,com-' and a position low enough so that the trolley with said table and a wheeled load thereon may move along said track under one other such wheeled table, and mechanism for raising and lowering said carriage, said carriage comprising pairs ofgirders adapted to interfit with girders on a table.

13. In mechanism of the class described, the

I combination with, means passing a wheeled vehicle over the ground, a pit below it. having wheel tables, each equipped with means detachably latching it across the pit, one of said t'ables having rail sections thereon and co'mprising longitudinal and cross girders secured together to form a rigid structure, and atrack in the bottom of said pit passing under said tables, of a trolley t-ravelable along said track, a table elevating carriage vertically reciprocable above the trolley, movable be- .tween aposition where it engages andlifts atable which it may be under high enough so its latching mechanism may be released, and a position low enoughso that the trolley with said table and a wheeled load'thereon may move alon said track under one other such-wheeled ta 1e, and mechanism'for raising and lowering said carriage, said carriage comprising girders to pass the cross-girders and engage the longitudinalgirders of a table.

14. In mechanism of the class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables, each equipped with means detachably latching it across the pit, one of said tables having rail-sections thereon and comprising'longitudinal and cross girders secured together to form a rigid structure,and a track in the bottom'of said pit assing under said tables, of a trolley travelab e along said track,

a table elevating carriage vertically reciprocal above the trolley, movable between a position Where it engages and lifts a table which it may be under high enough so its latch ng mechanism may be released, and a position low enough so that the trolley with sald table and a wheeled load thereon may move along said track under one other such wheeled table, and mechanismrfor raising and lowering said carriage, said carriage comprising pa rs of girders adapted to straddle the cross girders and engage the longitudinal girders oi a table.

15. In mechanism of the class described, the

combination with means passing a wheeled V movable between a position where it engages and lifts a table which it maybe under high enough soitslatching mechanism may be released, and a position low enough so that the trolley with said table and a wheeled load thereon may move along said track under one other such wheeled table, and mechanism for raising and lowering said carriage, said carriage comprising pairs of girders adapted to straddle the crossirders and engage the bot.- tom of the longitu inal 'irders of a table.

16. In mechanism of the class described, the

{combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables, each equipped with means detachably latching it across the pit, one of said tables having rail-sectionsthereon and comprising longitudinal and pairs of cross girders secured together to form a rigid structure, and

a track in the bottom o f said pit passing under said tables, of a trolley travela le along said track, a table elevating carriage vejrtmallyle ,movable etweenreciprocal above the tro a position where it engages andlifts a' table which it may be under high enough so its latching mechanism may be released, and a position low enough so that the trolley with said'table and a wheeled load thereon may move along said track under one other such wheeled table, and mechanism for raising and lowering said carriage, said carriage comprising pairs of girders adapted to straddle the pairs of cross-girdersand engage the longitudinal girders of a table.

1- In mechanism of the class describechthe combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables, each equipped with means detachably latching it across the pit, one of said tables having rail sections thereon and commay .move alon prising pairs of longitudinal girders underlying the rail sections, longitudinal girders at the sides of thetable and outside of the girders underlying the rail sections, and cross girders secured together to form a rigid structure, and a trackin the bottom of said pit passing under said tables, of a trolleytravelable along said track, a table elevating carriage vertically reciprocal above thetrolley, movable between a position where it engages and lifts a table which it may be under high enough so its latching mechanism may be re leased, and a position low enough so that the trolley with said table,and a wheeled load thereon may move along saidtrack under one other such wheeled table, and mechanism for raising and loweringsaid carriage.

18. In mechanism of the classdescribed', the

combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables, each equipped with'means (le tachably latching it across the pit, one of said ,7

tables having rail sections thereon and comprising pairs of longitudinal girders underlyingthe rail sections, longitudinal girders at the sides of the table and outsideof the girders underlying the rail sections, and cross girders extended under all of the longitudinal girders and secured thereto to form a rigid structure,

and a track in the bottom of said pit passing under said tables, of a trolley travelable along said track, a table elevating carriage verti-H cally reciprocal above the trolley, movable between a position where it engages and lifts a table which it may be under high enough so its latching mechanism may be released, and a' position low enough so that the trolley with said table and a wheeled load thereon may move along said track under one other such wheeled table, and mechanism for raising and lowering said carriag 19. In mechanism of the class described;

the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables, eachequipped with means detachably latching'itacross the pit, one of said tables having rail sections thereon and comprising a pair of longitudinal girders under each rail-section, longi tudinal girders at the sides of the table, and pairs of cross-girders underlying and extendmg across all of said longitudinal girders and secured thereto to form a rigid structure, and a track in the bottom of said pit passing under said tables, of a trolley travelable along said track, a table elevating carriage vertically reciprocal above the trolley, movable between a position where it engages and lifts a table which'it may be under high enough so its'latch-ing mechanism may be released, and a position low enough so that the trolley with said table and it wheeled load thereoh said track under one other such wheeled ta 1e, and mechanism for raismg and lowering said carriage.

20. In mechanism of the class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means detachably latching it across the pit,

and a track in the bottom of the pit passing under said tables, of a trolley travelable along said track, a table elevatmg carriage engageable with and separable from a table, on andsaid track under one other such wheel table,

, and mechanism for raising and lowering said,

carriage comprising screws rising from the trolley, rotatable gears around the screws and on the carriage, mechanism ,i'or driving the gears, and lubricant retaining cases around said gears.

21. In mechanism of the class described, the combination with means passing a wheeled wheel tables each equipped with means detachably latching it across the pit, and a track in tlic bottom of the pit passing under said tables, of a trolley travelable along said track, a table elevating-carriage engageable with and separable from a table,on and re ciprocal vertically above the trolley ggvable between a position where itiigagesand lifts a table high enough so its latching mechanism maybe released and a position low enough so that the trolley with said table and the wheeled load thereon may move along said track under one other such wheel table, and mechanism for raising and lowering said carriage comprising screws rising fromthe trolley, rotatable gears around the screws'and on the carriage, mechanism for driving the gears, and lubricant retaining cases around said gears, fixed to said carriage.

4.5 22. In mechanism of the class described, the

combination with means passing a wheeled vehicle over the ground, a pit below it having wheeltables'each equipped with means detachably latching it across the pit, and a-track in the-bottom of the pit passing under said tables, of a trolley travelable along said track,- a table elevating carriage engageable with and separable from a table, on and reciprocal vertically above the trolley, movable between a position where it engages and lifts a table high enough so its latching mechanism may be released and a position low enough sot-hat the trolley with said table and the wheeled load thereon may move along said track under one other such wheel table, and mechanism for raising and lowering-said carriage comprising screws rising from the trolley, rotatable gears around the screws and on the carriage,'worms engaging the gears, an electric motor on the carriage, connected to drive said vehicle over the ground, a pit below it having worms, and lubricant retaining cases in which said gears anc worms are mounted.

In mechanism of the class described,

the combination with means. passing .a wheeled vehicle over the ground, a pit below it having wheel tables, each equipped with means detachably latching it across the pit, and a track in the bottom of thepit passing under said tables, of a trolley travelable along said traclga'table elevating carriage separably engageble with a table, on'and reciprocal vertically above the trolley, movable between a position where it engages and lifts a table high enough so its latching mechanism may be released and a' position low enough so that the trolley with said table and a wheeled load thereon may move along said track under one other such wheel table, said carriage comprising pairs of girders fixedly secured together to form a rigid structure, and adapted to engage a-ta ble, and mechanism for raising having theirlower ends non-rotatably secured in the trolley, and their upper ends adapted to pass between the girders of said rotatable elements on the carriage.

24.111 mechanism of the class described, the combination with means passing a wheeledvehicle over the ground, a pit below it having wheel tables, each equipped with neans detachably latching it across the pit, and a track in the bottom of the pit passing under .saichtables, of a trolley travela'bl'c along said track, a table elevating carriage on and.reciprocal:vertically above the trolley, movablebetween a position where it engages and hits a table highenough so its latching mechanism may be-released and a position low enough so that the trolley with said table and a wheeled load thereon may move along said trackunder one other such wheel table, said carriage comprising pairs of girders fixedly secured together to torm'a rigid. structure and adapted to engage a table, mechanism for raising and lovveringthe carriage' comprising screws having their lowfcr ends pairs andnon-rotatably secured in the trolley and their and lowering the carriage comprising screi'vs each case being fixed to a pair of girders.

25. In mechanismof the class described, the combination with means passing"a' wheeled, vehicle over the ground, a pit be low it having wheel tables, 'each'equipped with means detachably latching it across the pit, and a track in the bottom of the pit pass lng under said tables, of a trolley travelable' along said track, a table elevating carriage on and reciprocal vertically above the trolley. movable between a position where it cnga .qe and lifts a table high enough soits latching mechanism may be released and a position wheeled vehicle over the ground, a pit be-- low it having wheel tables, each equipped low enough so that the trolley with said table and a wheeled load thereon may move along said track under one other such wheel table, said carriage comprising. pairsof girders fixedly secured together to, form a rigid structure and adapted to engage a table, mechanism for raising and lowering the carriage comprising screws having their lower ends non-rotatably securedin the trolley and their upper ends adapted to pass between the girders, rotatable elements on the carriage engaging the screws, and a motor on saidcarriage, and lubricant retaining cases around said elements and through which the screws pass, secured to and disposed under the girders.

,26. In mechanism of the class described, the combination with means passing a with means detachably latching it across the pit, and a track in the bottom of the pit passing under said tables, of a trolley travelable along said track, a table elevating carriage on and reciprocal vertically above the trolley, movable between a position where it engages and lifts a table high enough so its'latching mechanism may be released and a position low enough so that the trolley with said table and a wheeled load thereon may move along said track under one other such wheel table,

said carriage comprising girders hxedly sethe COIIIbIIIatIOII with means passlng a V cured together to form a rigid structure, and adapted to enga e a table, and mechanism for raising and owering the carriage comprisin screws having their lower ends nonrotata ly secured in the trolley and their,

upper ends adapted to pass between .the girders, rotatable elements on the carr age engagin the screws, driving mechanism for said cements, on the carriage, and cases for said elements, on which the girders are sup-' ported.

27. In'mechanism of the class described,

the combination with means passing a v enough so that the trolley with said table and wheeled vehicle over the ground, a pit below it having wheel. tables, e'ach equipped with means detachably latching it across the pit,and a track in the bottom of thg pit passing under said tables, of a trolley ravelable alongsaid track, a table elevating carriage on and reciprocal vertically above the trolley,

movable betweena position where it engages and lifts a table high enough so its latching mechanism ma be released and a position low enough so t at the'trolley with said table and a wheeled load thereon may move along said track under one other suchwheel table,

said carriage com rising girders fixedly se-f cure together to orm a rigid structure, and adap ed to engage a table, and mechanism for raising and lowering the carriage comprisin screws having their lower ends nonrotata bly secured in the trolley and their upper ends adapted to pass between the girders.

28. In mechanismof the class described,the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables, each equipped with means detachably latching it across the pit, and a track in thetbottom of the pit passing under said tables, of a trolley travelable along said .track,'a table elevating carriage on and reciprocal vertically above the trolley, movable between a position where it engages and lifts a table high enough so its latching mechanism may be released and aposition low enough so that the trolley with said table and-a wheeled load. thereon may move along said track under one other such wheel table, said carriage comprising girders fixedly secured together to form a rigid structure, and adapted to engage a table, and mechanism for raising and lowering the carriage comprising screws having their lower ends nonrotatably securedin the trolley and their upper ends adapted to pass between the girders, rotatable elements on the carriage, engaging the screws, and an electric motor connected to drive said elements, mounted on the carriage and between the girders.

29. In mechanism of the class described,

wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means detachably latching it across thepit,

one of said tables having rail-sections thereon, and a track in the bottom of the pit passing under said tables, of a trolley travelable along said track, table elevating means engageable with and separable from the table, on and reciprocal vertically above the trolley, .mov-

able between a position wherelit engages and lifts a table high enough so its latching mechanism may be released and a position low ithaving wheel tables each equipped with means detachably. latching it across the pit one of said tables having rail sections thereon, and a track in the bottom of the pit pass ing under said tables, of a trolley travelable along said track, table elevating means en gageable with and separable from the table,

on and reciprocal vertically above the .trolley, between a position where it engages and lifts a table high enough so its latching mechanism may be released and a position low enough so that the trolley with said tableand a wheeled load thereon may move along means detachablyiflatching it in pit-bridging said track under one other such wheel table,

and mechanism for raising and lowering said latching means comprising a set of laterally slidable bolts under and in the vertical planes of the rail sections.

position, one of said tables having rail-sec tions thereon and comprising rigidlyfconnected girders underlying the rail-sections and forming a part of the 'table, said.latching means comprising laterally slidable bolts in the horizontal plane of the girders,

and atrackin the bottom of said pit passing under said tables, of a trolley travelable along said track, a table elevating carriage engageable with and separable from a table, on and above the trolley and reciprocal vertically between a position where it engages and lifts a table which it may be under high'enough so its bolts may be released, and a position low enough so that the trolley with a wheeled load thereon may move along under one other such table, and mechanism for raising and lowering the carriage.

1 32. In mechanism of the class described,

I the combination with means passing a wheeled vehicle over the ground,'a pit below it having wheel tables each'equipped with means detachably latching it in pit-bridging position, one of said tables having rail-sections thereon and comprising rigidly connected girders underlying the rail-sections and forming a part of the table, said latching means comprising laterally slidable bolts disposed in the horizontal plane of the girders,

and a track in the bottom of said pit passing under said tables, of a trolley travelable along said track, a table elevating carriage engageable'with and separable from the table, on.

and above the trolley, and reciprocal vertically, movable between a position where it engages and lifts a table which it may be under high enough so its bolts may be released, and

a position low enough so that the'trolley with a wheeled 103a thereon may move along under one other such table, and mechanism for raising and lowering the carriage, comprising screws on the trolley and elements on the carriage and engaging the screws.

33.-"In mechanism of the class described,

" the combination with means passing a wheeled vehicle 'over the ground, a pit below it having wheel tables each equipped with means detachably latching it across the pit,

one of said tables having rail sections there on and comprising rigidly connected girders underlying the r'aiLsections and forming a part of the table, said latching means com prising laterally slidable bolts in thehorizontal plane of the ,girders, and a track in the bottom of said pit passing under said tables,

of'a trolley, travclable along said track, a table elevating carriage engageable with and separable from a table, on and above the 34. In mechanism of the class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means detachably latching it across the pit,

"one of said tables having rail sections there on and comprising girders underlying and extending longitudinally of the rail sections and cross-girders beneath :the longitudinal girders, said latching means comprising lateral-ly slidable bolts above the plane ofthe cross-girders, and a. track inthe bottom of said pit passing under said tables, of a trolley travelable along saidv track, a table eleyating carriage on and reciprocal vertically above the trolley, movable between the position where it engages and liftsa table which it may be under high enough so its bolts may be released, and a position low enough so that the trolley with a wheeled load thereon may move along under one other such table, and mechanism for raising and lowering the carriage.

35. In mechanism of the class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means detachably latchinoit in pit-bridging position, one of said tables having rail sections thereon and comprising pairs of rigidly connected girders underlying and extending longitudinally of the rail sections, said latching means comprising laterally slidable bolts mounted within the airs of girders, and a track in the bottom 0? said pit passing under said tables, of a trolley travelable along said track, a table elevating carriage on and reciprocal vertically above the trolley, movable between the position where it.engages and lifts a table which it may be under high enough so its bolts may be released, and a pothe combination: with means passing1 a beow wheeledvehicle over the ground, a pit it having wheel tables each equipped With means detachably latching it across the pit, one of said tables having rail-sectionsthereon and comprisingrigidly connected pairs of girders underlying and-extending longitudinally of the rail-sections and forming a part of the table, said latching means comprising bolts slidable in guides within the pairs of girders, and a track in the bottom of said pit passing under said tables, of a trolley travelable along said track, a table elevating carriage on and reciprocal vertically above the trolley, movable between the posltlon where it engages andlifts a-tab-le which it may be under high enough so its bolts may ber'eleased, and a position low enough so that the trolley with a wheeled load thereon may move along under one other such table, and mechanism for raising and lowering the carriage.

37. In mechanism of the class described, the combination with means passing a wheeled vehicle over the-ground, a pit'be-' low it having wheel tables, each equipped with means detachably locking it acrossthe pit, one of said tables having rail-sections Y thereon, and a track in the bottom of the pit passing under said tables, of a trolley'travelable along said track comprising longitudinally extending girders and cross girders, a table elevating carriage, separably engageable with a table, on and reciprocal vertically above the trolley, movable between a position where it engages and lifts a table high enough so its latching mechanism may be released, and a position low enough so that the trolley with said table and a wheeled load thereon may movev along said track under one other such wheel table, said carriage comprising girders fixedly secured together to form a rigid structure, and mechanism for raising'and lowering the carriage comprising screws and power. mechanism mounted on the carriage, the carriage being lo'werable between t he' girders on the trolley.

38. In mechanism oTthe class described, ,the combination with means passing a wheeled vehicle over theground, a pit below it having wheel tables, each equipped with means detaehably locking it across the pit, one of said tables having rail-sections there,- on, and a track in the bottom of the pit passing under said tables, of atrolleyrtravelable along said track "comprising longitudinal girders and cross-girders on top and at the ends of saidtlongitudinal girders, a table 'ele vating carriage comprising rigidly connected girders, separably en ageable with a table, on and reciprocal vertlcally above the trolley,

and movable between a position where it engages and lifts a table high-enough so its latching mechanism may be released, and a position low enough so that the trolley with said table and a wheeleddoadLhereon ma move along said track under one other suc i a table higp may be 1 eased and a position low enough wheel table, and mechanism for raising and loweringsaid carriage, comprising screws on the trolley and power-mechanism on the carria ge, said carriage being loWerable between the cross-girders of the trolley.

39. In mechanism of the class described,-

ing under said tables, of a trolley travelable,

along said track, comprising pairs of spaced longitudinal girdersand cross-girders on top of the longitudinal girders,'a table elevating carriage separably engageablewith a table, on and reciprocal vertically above the trolley,

and'movable between a position where it engages and lifts a tablehigh enough so its latching mechanism may be released and a position low enough so that the trolley with said table and a wheeled load thereon may move along said track under one other such wheel table, said carriage comprising girders fixedly secured together to form a rigid structure, mechanism for raising and lowering the carriage comprising screws and power mech-' anism mounted on the carriage, and blocks fixed between the spaced girders of the longitudinal pairs of the trolley, in which said screws are fixedly secured.

40.'In mechanism of the .class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having Wheel tables each equipped with means detachably latching it across the pit, and a track in the bottom of the pit passing under said tables, of a trolley travelable along said track, a table elevating carriage engageble with andseparable from-the table, on and reciprocal vertically above the trolley, movable between a position Where it engages and lifts a table high enough so its latching mechanism may be released and a position l'ow enough so that the trolley with said table and the wheeled load thereon may move along said track under one othersuch wheel table,

mechanism for raising and lowering said car- 'riage comprising an electrlc motor mounted on said carriage, and means independent of tachably latching it across the pit, and a track in. the, bottom of the pit passing under said tables, of a trolley travelable along said track,

a table elevating carriage engageable with and separable from the table, on and reciprocal vertically above the trolley, movable between a position'where it engages and lifts enough so its latching mechanism track under one other such whjeel table, mech anism for raising and lowering said carriage combination with means passing a-wvheeledr comprising an electric motor mounted on said propelling the trolley.

42. In mechanism of the class described, the

carria e, and manually operable gearing for combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables each equipped with'means detachably latching it across the pit, and a track in the bottom of the pit passing under said tables,of a trolley travelable along said track, a table elevating carriage engageable with and separable from the table, on and reciprocal vertically above the trolley, movable between a position where it engages and lifts a table high enough so-its latching mechanism'may' be released and a position low enough so that the trolley with said table and the wheeled load thereon may move along said track'under one other such wheel table, mechanism for raising and lowering said carriage comprising an electric motor mounted on said carriage, and manually operable gearing for propelling the trolley, comprising a toothed wheel, a dog engageable with the toothed wheel and a hand-lever 'for operating said d g a. I v

43. In mechanism of the class described, the

vehicle over the ground,,a pit below it having wheel tables, each equipped with-means 'detachably latching it across-the pit, one ofsaid tables having rail-sections thereon and com-- prising "rigidlymounted longitudinal and cross-girders,"a'nd a track in the bottom ofsaid pit passing under said tables, of a trolley travelable along said track, a table elevating carriage of girder construction, separably engageable with a table/on, and vertically reciprocable above the trolley, movable between a position where it engages and lifts a table 'which it may be under high .enough so its latching mechanism may be released and a position low enough so that the,trolley with ail) ' said table anda wheeled load thereon may move along said track under one rather such wheeled table, mechanism for raising and lowering said carriage comprising screws on the trolley and power mechanism on said carriage, and a set of guides retaining a table in proper position on the carriage.

44. In mechanism of the class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables, each equipped with means detachably latchin it across the pit, one of said tables having ra1l-sections thereon andcomprising rigidly connected longitudinal and cross-girders, and a track in the bottom of said pit passing under saidtables, of a trolley travelable along said track, a table-elevating carriage of girder construction, separately on said carriage, and a set of guides coacting with the girders of a table to properly position and retain it on the carriage. p

45. In mechanism of the class described, the j combination with means passing a wheeled vehicle over the ground, a pit below it havdetachably latching it across the pit, one of said tables having rail-sections therein and comprising rigidly connected longitudinal and cross'girders, and a track'in the bottom of said pit passing under said tables, of a trolley travelable along said track, a table elevating carriage of girder-construction, separately engageable with a table, on and vertically reciprocable above the trolley,

movable between a position where it engages and lifts a table which it may be under high enough so its latching mechanism may be released, and a position low enough so that the trolley with said table and a wheeled load thereon may move along said track under one other such wheeled table, mechanism for raising and lowering said carriage comprise 'ing screws on the trolley and power mecl1a ing "wheel tables, each equipped with means nism on said carriage, and a set of guides projecting upwardly from the carriage to lap the girders of a table and retain it in proper position on the carriage.

46. In mechanism of the class described, the combination with means passing a wheeled vehicle over the ground, a pit below it having-wheel tables each equipped with means detachably latching it across the pit,

eand a track in the bottom of the pit passing winder said tables, of a trolley travelable along said track, a table elevating carriage, engageable with and separable from'a table, on and reciprocal verticall above the trolley, movable between a position where it engages and lifts a-table.high enough so its latching mechanism may be released and a position low enough so that the trolley with saidtable and a wheeled load thereon may move along said track under one other such wheel table, and power means for raising and loweriiig said carriage comprising a multiplicity of stationary screws rising from the trolley and rotatable elements around the screws and on said table-engaging carriage. 47. In mechanism of the class described,

the combination with means passing a wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means detachably-latching it across the pit, and a track in the bottom of the pit passing under said tables, 'of a trolley travelable along said track, a table elevating carriage engageable with and separable from a table,

on and reciprocal vertically above the trolley, movable between a position where it engages and lifts a table high enough so its latching mechanism may be released and 'a position low enough so that the trolley with said table and a wheeled load thereon may move along said track wheel table, and power-means manipulating said carriage comprising a multiplicity of stationary screws rising from the trolley, rotatable elements on the screws, and gearing for conjointly rotating said elements, said elements and gearing being carried on' the table-engaging carriag r b 48. In mechanism of the class described, the combination with means passing a ,wheeled vehicle over the ground, a pit below it having wheel tables each equipped with means detachably latching it across the pit, and a track in the bottom of the pit passing under said tables, of a trolley travelable along said track, a table elevating carriage separably engageablewith a table, on and reciprocal vertically above the trolley, mov able between a position where it engages and lifts a table high enough so its latching under one other such.

said table and a wheel insuring proper and power means for raising and lowering said carriage comprising a'multiplicity of stationary screws rising from worm wheels traversing in unison said screws, and a motor, said worm wheels and motor being carried'on said carriage.

49.-In mechanism of the class described,

in combination with means passing a wheeled vehicle over the ground, and a pit below it, having a multiplicity of separated wheel tables each equipped with means cletachably latching it across said pit, a track in the bottom of the t passing under said tables, a trolley trave able along said track, table elevating means on tically above-the trolley, movable between a position where it engages and lifts a table which itmay be under, high enough so its latching mechanism may position low enough so that the trolley with load thereon may move along said track other such wheel tables, and angular guides interfitting of the table elevating means and adjacent wheel table.

osoAR L. COFFEY and reciprocalverunder one 'or more the trolley,

be released, and a 

